光伏晶体中复色宽光束的调制不稳定性研究  

Study on Modulation Instability of Broad Polychromatic Beams in Photovoltaic Crystal

作　　者：彭小兰[1] 周亚民[2] 王红成[1] 

机构地区：[1]东莞理工学院电子工程学院,广东东莞523808 [2]东莞理工学院化学与环境工程学院,广东东莞523808

出　　处：《光学学报》2011年第2期202-207,共6页Acta Optica Sinica

基　　金：东莞市科技计划项目(200910814038);广东省高校优秀青年创新人才培养计划项目(LYM10124)资助课题

摘　　要：研究了在有均匀背景光照明的光伏光折变晶体中两种具有不同频率的宽光束的调制不稳定性。结果表明,复色宽光束的调制失稳可以由两信号光对背景光的Glass系数比r1和r2来控制,且其调制失稳增长率还依赖于复色光中两分量成分的强度f与g之比。对于r1>1且r2>1的情况,当f<0.5时,随着g的增大,最大调制不稳定性增益先随之增大而后减小;而当f>0.5时,最大调制不稳定性增益随着g的增大而减小,当g取足够大的值时调制不稳定性受到抑制,从而趋近于0。对于r1>1,r2<1的情况,当f<4时,对应于r2<1的信号光可以抑制甚至完全禁止另一束对应于r1>1的信号光的调制不稳定性,而f>4时调制不稳定增益比较小。在r1<1,r2<1时两复色宽光束不发生调制失稳。The modulation instability of two broad beams with different frequencies is investigated in a photovoltaic photorefractive crystal with a uniform background illumination. It is shown that modulation instability of broad polychromatic beams can be adjusted and controlled by the Glass coefficient ratios （r1, r2） of the signal and background beams. It is also found that the strength of modulation instability depends on the ratio of beam intensities f and g. For the case of r1〉1, r2 〉1, the maximum modulation instability gain increases first and then decreases with the increase of g when f〈0.5, while it decreases monotonically when f〉0.5. For large g, the modulation instability is suppressed and tends to be 0. For the case r1 〉 1, r2 〈1, the signal beam whose r2 is less than 1 can suppress the modulation instability of the other signal beam whose r1 〉 1 when f〈4. If f〉4, the modulation gain is always very small. For the case r1〈1, r2〈1, the Dolvchromatic broad benms do not undergo modulation instability.

关 键 词：非线性光学 调制不稳定性 光伏效应 复色光 

分 类 号：O43[机械工程—光学工程]